Description

Awnings are roof-like shelters installed on a home’s exterior to shade windows from the sun’s heat, glare, and damaging ultraviolet (UV) rays. Awnings can also shade outdoor living spaces. By blocking the sun’s radiation outside of the home, before it reaches windows, awnings can be far more effective than interior blinds and shades at reducing indoor temperature increases from sunlight (solar heat gain).

Awnings are available in a wide range of colors and patterns. Stationary awnings are typically made of a durable fabric but can also be made of metal or fiberglass. They usually have a fixed aluminum frame and are designed for seasonal removal.

Retractable awning frames typically have hinged arms that allow for extension. Many retractable models are fully adjustable, providing tremendous flexibility in how much shade they provide. The awning fabric rolls up where the unit is attached to the building, with the roll often housed in a protective cover. Retractable awnings are often operated by a durable motor controlled by a wireless remote or hard-wired switch; manual operation with a long-handled crank or pull cord is a lower-cost option. Sophisticated controls on higher-end retractable awnings allow automatic extension in full sunlight and automatic retraction when high wind is detected.

Overall Thermal Performance

Although awnings are most commonly used to reduce solar heat gains in southern climates, they can also save energy in northern climates by reducing summertime solar heat gain. Awnings also provide shelter from direct solar radiation on patios or decks, for a comfortable outdoor environment on sunny days.

Awnings can affect thermal performance in two ways—reducing unwanted solar heat gain during periods when cooling is needed and enabling desirable solar heat gain during periods when heating is needed. Ideally, stationary awnings are configured and placed based on energy analysis or modeling to optimize shading performance throughout the year for a specific location on the home. Custom configuration of stationary awnings may be common for commercial buildings, but not
for most residential installations.

On a south wall, it is fairly easy to configure stationary awnings to block unwanted direct-beam summer sunlight while allowing desired lower-angle winter sunlight to reach the window. On east and west walls, because of low solar angles during early morning (east) and late afternoon (west) hours, awnings are not as effective unless they incorporate well-designed side coverings or can be extended to fully cover the entire window.

The benefits of retractable awnings are that they can be kept fully or partially retracted to allow beneficial sunlight into the home in cooler seasons, and extended when solar heat gain causes interior overheating or the need for air conditioning.

Awnings do not reduce heat loss through windows other than reducing exposure to nighttime sky radiation, which can reduce condensation potential in cold climates.

This stationary awning with closed-in sides provides nearly complete solar shading and only limits view of the sky.Photos: Professional Awning Manufacturers Association

Key Benefits

Reduce glare

Reduce UV damage to home interiors

May enhance building’s appearance

Direct rain away from the window

May reduce winter nighttime condensation

Effectively block solar heat gain while maintaining much of view

Maintain window egress

Key Drawbacks

Customization needed for optimum performance in some cases, particularly for fixed awnings; may affect aesthetics.

If deep enough to block most direct solar heat gain on east and west, may block more daylight and view than desired (adjustable awnings mitigate this problem).